Tank drain valve with a rod concentric with valve member to pierce sedimentary layer in tank

ABSTRACT

A valve comprising a body adapted to be associated with an opening in the wall of a fluid reservoir or flowline, to provide a flow path, from an inlet (111) at the opening, to an outlet (114), a valve seat (117) located across the flow path at the inlet (111), a valve member (116) movably supported from the body to be movable between a closed position at which it is in sealing engagement with the valve seat (117) and an open position at which it is spaced from the valve seat (117), an elongate clearing element (128) which is slidably supported from the valve member (116), said clearing member (128) having an outer end (129) which is movable towards and away from the valve member (116) between an extended position at which it extends from the valve member (116) through the valve seat (117) beyond the opening and a retracted position closely adjacent the valve (116) member, a drive means (120) to cause movement of the valve member (116) between the open and closed positions and to cause movement of the clearing member (128) between the extended and retracted positions.

This invention relates to a valve and in particular it relates to avalve which is to be used in installations where there is a likelihoodof sedimentation or scaling in the region of the flow path which is tobe controlled by the valve.

The valve has a particular application to installations where liquorsare stored in vats or reservoirs which are associated with a drainprovided with a valve. In many cases, while the liquor is maintained ata particular condition such as above a predetermined temperature, atwhich there is usually no precipitation or sedimentation. However,sedimentation can occur at critical times and when the conditions suchas temperature vary and this can be particularly prevalent in the regionof a drain which is generally associated with a well formed in the wallof the vat or reservoir. As a result of the well the liquor contained inthe well is subject to cooling and often is stagnant. As a resultprecipitation or sedimentation will occur in the region of the drain,and it is often the situation that when the drain valve is opened, thebuild up of deposits in the region of the drain aperture can result in ablockage which prevents an adequate flow of liquor from the drain. Itthen becomes necessary to attempt to clear the aperture from the surfaceof the liquor or through the open valve by some external tool or thelike. Such an arrangement is not only difficult but can be extremelyhazardous to the personnel and can result in damage to the vat, anddrain.

Some arrangements have been proposed in the past to provide means inassociation with valves which can be used to clear a fluid pathwayupstream from a valve in order to ensure a flow of fluid on the valvebeing opened. Examples of these arrangements are disclosed in U.S. Pat.No. 1,467,492, U.S. Pat. No. 2,530,433, U.S. Pat. No. 3,211,422, U.S.Pat. No. 4,391,289 and U.S. Pat. No. 4,192,342. A difficulty with manyof these prior art devices however is the dependent nature of theclearing action with the movement of the valve member towards and awayfrom the valve seat. In addition it is necessary to ensure that once thevalve is opened that sufficient clearance exists for any particles ofsolid material that have been created prior to the opening of the valveby the clearing action and/or which are in the region of the openingprior to opening will be able to pass through the opened valve withoutobstructing the flow through the valve. It is also desirable that theclearing means be able to move past the valve seat and into the volumeassociated with the valve in order to be able to penetrate any layer ofsediment that has built up over the outlet and to provide an openingthrough the layer of sediment or scale.

It is an object of this invention to provide a valve which can beutilised in circumstances where sedimentation or scaling can occur whichcan otherwise limit an adequate fluid flow through the valve, when open.

Accordingly, the invention resides in a valve comprising a body adaptedto be associated with an opening in the wall of a fluid reservoir orflowline, to provide a flow path, from an inlet at said opening, to anoutlet, a valve seat located across the flow path at the inlet, a valvemember movably supported from the body to be movable between a closedposition at which it is sealing engagement with the valve seat and anopen position at which it is spaced from the valve seat, an elongateclearing element which is slidably supported from the valve member, saidclearing member having an outer end which is movable towards and awayfrom the valve member between an extended position at which it extendsfrom the valve member through the valve seat beyond the opening and aretracted position closely adjacent the valve member, a drive means tocause movement of the valve member between the open and closed positionsand to cause movement of the clearing member between the extended andretracted positions.

According to a preferred feature of the invention the clearing elementis movable with the valve member on movement of the valve member betweenthe closed and open positions. It is a further preferred feature thatthe clearing member is also movable independently of the valve memberbetween its extended position and its retracted position when the valvemember is at least at both its closed and open positions.

According to a further preferred feature the clearing element issupported from the valve member to be rotatable about its central axis.In this regard it is a further feature of the invention that theclearing element can be caused to rotate about its central axis duringits movement between the extended and retracted position.

According to a further preferred feature of the invention the outer endof the clearing element is provided with a wear resistant cuttingelement. In a preferred form the outer end of the clearing element has adiameter substantially corresponding to the diameter of the valve seat.

According to a further preferred feature of the invention the drivemeans comprises a fluid operated member associated with the valve memberand the clearing member. If desired a separate fluid operated member canbe associated with the valve member and the clearing element.

According to one particular embodiment of the invention the valve memberis of an elongate configuration and is movable axially into and out ofengagement with the valve seat. A further feature of the embodiment thevalve member Is cylindrical in shape. It is a further feature that thevalve member is provided with a first seal at one end which is proximatethe valve seat wherein the first seal is in engagement with the valveseat when the valve member is at its closed to sealingly close thevalve. According to a further preferred feature of the embodiment thedrive means includes said valve member being provided with a second sealat a position spaced from the one end, said second seal being receivedin a cylindrical first chamber which is concentric to the valve member,said second seal defining two sub-chambers within the chamber and saidsub-chambers being capable of being pressurised to effect said movementof the valve member.

In one form of the above embodiment the second seal is located at theother end of the valve member. It is a further feature of the embodimentthat the inner portion of the clearing element is provided with a thirdseal which is received in the one sub-chamber remote from the openingand which subdivides the one sub-chamber into two further sub-chamberssaid further sub-chambers being capable of being pressurised to effectsaid movement of the clearing element.

According to an alternative form of the embodiment the second seal islocated intermediate of the length of the valve member. According tothis form the other end of the valve member extends beyond the chamber.In addition the valve member is hollow and a second chamber is definedwithin the valve member around the portion of the clearing elementreceived therein and wherein the portion of the clearing element isprovided with a third seal which is received in the second chamber tosubdivide the second chamber into two further sub-chambers said furthersub-chambers being capable of being pressurised to effect said movementof the clearing element.

According to a further preferred feature of the invention a lockingmeans is provided between the valve member and the body to selectivelylock the valve member in position.

According to a further preferred feature of the invention asubstantially unobstructed flow path is provided in the body between theinlet and the outlet when the valve member is in the open position andthe clearing member is in the retracted position. According to anembodiment of the invention this is achieved by providing that the crosssectional dimensions of the flow path are at least equal to the crosssectional dimensions of the valve seat.

The invention will be more fully understood in the light of thefollowing description of several specific embodiments. The descriptionis made with reference to the accompanying drawing of which:

FIG. 1 is a sectional side elevation of a valve according to the firstembodiment with the valve member in the open position and the clearingelement in the retracted position;

FIG. 2 is a sectional side elevation of a valve according to the firstembodiment with the valve member in the open position and the clearingelement in the partially extended position;

FIG. 3 is a sectional side elevation of a valve according to the firstembodiment with the valve member in the closed position and the clearingelement in the retracted position;

FIG. 4 is a sectional side elevation of a valve according to the firstembodiment with the valve member in the closed position and the clearingelement in the partially extended position;

FIG. 5 is a sectional side elevation of a valve according to the secondembodiment with the valve member in the open position and the clearingelement in the retracted position;

FIG. 6 is a sectional side elevation of a valve according to the secondembodiment with the valve member in the open position and the clearingelement in the partially extended position;

FIG. 7 is a sectional side elevation of a valve according to the secondembodiment with the valve member in the closed position and the clearingelement in the retracted position;

FIG. 8 is a sectional side elevation of a valve according to the secondembodiment with the valve member in the closed position and the clearingelement in the partially extended position;

The valve of the first embodiment as shown at FIGS. 1, 2, 3 and 4comprises a hollow body 10 which defines a passage having an inlet 11and an outlet 14 which are of uniform cross section and are offset fromeach other by 90 degrees. The inlet is provided at its outer end with aflange 12 which is engagable with the wall (not shown) of a vat tosurround a drain hole (not shown) provided in the wall. The flange 12 isprovided with a set of holes 13 which are receivable over studs providedin the wall of the vat.

The portion of the inlet 11 of the body 10 is provided with a valve seatwhich is engagable by a valve member 16 supported from a tubularextension 15 of the inlet portion of the hollow body. The valve member16 is cylindrical and is provided with a suitable O-ring seal 18 at itsinner end which engages with the valve seat 17 to close the valve, onmovement of the valve member 16 such that its inner end is receivedwithin the valve seat 17 (see FIGS. 3 and 4).

The tubular extension 15 of the body is associated with a hydrauliccylinder having a chamber 19 which is defined by an outer cylindricalhousing 20 fixed at one end 21 to the free end of the tubular extension15 and which is closed at its other end 22 by an end cap 23. The outerend of the valve member 16 is received within the chamber 19 and isprovided with a piston element 24 which is provided with an O-ring seal25 and which sealingly subdivides the chamber 19 into a first portion Abetween the tubular extension 15 and the piston 24 and a second portionB between the end cap 23 and the first piston 24. A first port 26 isprovided in the wall of the body 10 to provide communication into thefirst space A while a second port 27 is provided in the wall of thecylindrical housing 20 to provide communication with the second space B.

The valve member 16 slidably accommodates a clearing element whichcomprises a rod 28 which is concentrically sealingly and slidablysupported within the valve member 16 to be capable of axial movementwithin the valve member, One end of the rod which is received in theinlet 11 of the hollow body 10 and is provided with a cap member 29while the other end of the rod 28 is located within the second portion Bof the chamber 19 and is provided with a second piston 30 which isprovided with a pair of O-ring seals 31 and which sealingly engages withthe internal wall of the cylindrical body 20 to subdivide the secondspace B within the chamber into the portion B' between the first piston24 and the second piston 30 and a third space B" between the end cap 23and the second piston 30. The end cap 23 is provided with a third port32 which provides communication with the third space B".

The valve according to the first embodiment is intended to be utilisedin association with the drain of a vat or a like storage vessel andwhich is intended to be in the normally closed position (see FIGS. 3 and4) at which position the seal 18 of the valve member 16 is sealinglyreceived in the valve seat 17. Where the liquor which is accommodatedwithin the vat may be subject to sedimentation or scaling, there is avery strong likelihood that the zone above the drain outlet may becovered by sediment or scale. Therefore if the valve is opened wherebythe seal 18 of the valve member 16 is withdrawn from engagement with thevalve seat 17, to the retracted position as shown in FIGS. 1 and 2,there will be a restricted flow or no fluid flow from the drain outlet.In order to provide a full flow from the opened valve, the clearingelement is moved axially from a retracted position at which the capmember 29 is accommodated within the inner end of the valve member 16 toan extended position at which it extends into the volume of the vat (asshown at FIG. 4) to penetrate the layer of scale or sediment which hascollected within the region of the drain hole in order to clear suchscale or sediment away from the drain hole prior to opening of thevalve. The clearing element may then be withdrawn into engagement withthe inner end of the valve member 16 (as shown at FIG. 3) and then thevalve member 16 can be withdrawn from engagement with the valve seat 17As shown at FIG. 1).

The movement of the clearing element between its retracted position andits extended position, and of the valve member 16 between its sealingengagement with the valve seat and its retracted position as shown inthe drawing can be effected by application of fluid pressure to therespective spaces A, B' and B"" within the chamber 19 provided in thehydraulic cylinder. If desired the movement of the clearing elementbetween the retracted position and the extended position may be effectedwhen the valve member 16 is in its retracted position by application ofpressure into the third space B" and venting of the second space B' andmaintaining pressure in the third space A.

The cap member 29 on the one end of the clearing element is provided atits outer end with a cutting tip 33 which is formed of a wear resistantmaterial and which is configured to enhance penetration of any depositcollecting in the region of the drain hole.

The valve of the first embodiment provides a means of ensuring that theregion upstream of the valve is clear prior to the valve being openedand of ensuring that the region upstream of the valve remains clearduring the period that the valve is open. In addition the valve memberwhen retracted away from the valve seat ensures a clear passagewaybetween the inlet 11 and the outlet 14 and as a result any detritus orpieces of sediment which are dislodged as a result of the action of thecutting tip will pass through the hollow body without causing anobstruction. Furthermore the configuration of the valve member is thatit is substantially cylindrical and as a result when it is intermediateof the retracted and extended position it is not possible for detritusor pieces of sediment that are dislodged by the action of the cuttingtip to become jammed between the wall of the hollow body and the valvemember and which will prevent the full opening of the valve.

If desired the valve may be associated with a control means which willperiodically activate the delivery of fluid to the second and thirdspaces B' and B" respectively to cause the clearing element to becyclically moved from the retracted position to the extended positionand then to the retracted position to maintain the region above thevalve member and drain clear of sediment. This cyclic action may beeffected manually or automatically.

The valve of the second embodiment as shown at FIGS. 5, 6, 7 and 8comprises a hollow body 110 which defines a passage having an inlet 111and an outlet 114 which are of uniform cross section and are offset fromeach other by 90 degrees. The inlet 111 is provided at its outer endwith a flange 112 which is engagable with the wall (not shown) of a vatto surround a drain hole (not shown) provided in the wall. The flange112 is provided with a set of holes 113 which are receivable over studsprovided in the wall of the vat.

The inlet 111 of the body is provided with a valve seat 117 which isengagable by a valve member 116 supported from a tubular extension 115of the inlet portion of the hollow body. The valve member 16 iscylindrical, hollow and is provided with a suitable O-ring seal 118 atits inner and which engages with the valve seat 117 to close the valve,on movement of the valve member 116 such that its inner end is receivedwithin the valve seat 117 (see FIGS. 7 and 8).

The tubular extension 115 of the body is associated with a hydrauliccylinder having a chamber 119 which is defined by an outer cylindricalhousing 120 fixed at one end to the free end of the tubular extension115 and which is closed at its other end by an annular end cap 123. Thevalve member 116 is received slidably and sealingly received withintubular extension 115 and the end cap 123 such that it is receivedthrough the chamber 119 and is provided with a piston element 124 whichis provided with an O-ring seal 125 which sealingly subdivides thechamber 119 into a first space 141 between the tubular extension 115 andthe piston 124 and a second space 142 between the end cap 123 and thefirst piston 124. A first port 126 is provided in the wall of thetubular extension 115 to provide communication into the first space 141while a second port 127 is provided in the side of the end cap 123 toprovide communication with the second space 142.

The valve member 116 slidably accommodates a clearing element whichcomprises a rod 128 which is concentrically sealingly and slidablysupported within the valve member 116 to be capable of axial movementwithin the valve member. One end of the rod 128 is received in the inlet111 of the hollow body and is provided with a cap member 129 while theother end of the rod 128 is slidably received in a second end cap 144mounted at the other end of the valve member 116. The intermediateportion of the rod member 128 which is located within the hollow valvemember 116 is provided with a second piston 130 which is provided withsuitable seals 131 which sealingly engage with the internal wall of thehollow valve member 116 to provide a second pair of sub-chamberscomprising a third space 146 which is innermost and a fourth space 147which is outermost within the valve member 116. The second end cap 144which closes the outer end of the valve member 116 is provided with athird port 149 which communicates with the innermost third space 146through a passageway 150 formed axially through the wall of the valvemember and an opening 151 which extends between the passageway 150 andthe third space 146. The second end cap 144 is also provided with afourth port 132 which provides communication into the outermost fourthspace 147.

The valve according to the second embodiment is intended to be utilisedin association with the drain of a vat or a like storage vessel andwhich is intended to be in the normally closed position (see FIGS. 7 and8) at which position the seal 118 of the valve member 116 is sealinglyreceived in the valve seat 117. Where the liquor which is accommodatedwithin the vat may be subject to precipitation, or sedimentation whichis likely to cause scaling, there is a very strong likelihood that thezone above the drain outlet may be covered by sediment or scale.Therefore if the valve is opened whereby the seal 118 of the valvemember 116 is withdrawn from engagement with the valve seat 117 (asshown at FIGS. 7 and 8), to the retracted position as shown in FIGS. 5and 6, there will be a restricted flow or no fluid flow from the drainoutlet. In order to provide a full flow from the opened valve, theclearing element is moved axially from a retracted position at which thecap member 129 is accommodated adjacent the inner end of the valvemember 116 to an extended position at which it extends into the volumeof the vat (as shown at FIG. 8) to penetrate the layer of scale orsediment which has collected within the region of the drain hole inorder to clear such scale or sediment away from the drain hole prior tothe opening of the valve. The clearing element may then be withdrawninto engagement with the inner end of the valve member 116 (as shown atFIG. 7) and then the valve member 116 can be withdrawn from engagementwith the valve seat 117 (as shown at FIG. 5).

The movement of the valve member 116 between its sealing engagement withthe valve seat and its retracted position as shown in the drawing can beeffected by application of fluid pressure to the first and second spaces141 and 142 within the chamber 19 provided in the hydraulic cylinderwhile the movement of the clearing element between its retractedposition and its extended position can be effected by application offluid pressure to the third and fourth spaces 146 and 147 within thevalve member 116. If desired the movement of the clearing elementbetween the retracted position and the extended position may be effectedwhen the valve member 116 is in both its retracted and extended positionby application of pressure into the fourth space 147 and venting of thethird space 16. Similarly the clearing element can be moved from theextended position and the retracted position by the application of fluidpressure to the third space 146 and venting the fourth space while thevalve member 116 is in its retracted or extended position.

The cap member 129 on the one end of the clearing element is provided atits outer end with a piercing tip 133 which is formed of a wearresistant material and which is configured to enhance penetration by thecap member of any deposit collecting in the region above the drain hole.

In addition the cap member has a diameter corresponding to that of thevalve seat 117 or a little less then the valve seat 117. This ensuresthat the clearing member clears any deposits from the valve seat 117when it is caused to be moved to and from the extended position whilstthe valve is in the open or retracted position as shown at FIGS. 5 and6.

The valve of the second embodiment provides a means of ensuring that theregion upstream of the valve is clear prior to the valve being openedand of ensuring that the region upstream of the valve remains clearduring the period that the valve is open. In addition the valve memberwhen retracted away from the valve seat ensures a clear passagewaybetween the inlet 111 and the outlet 114 and as a result any detritus orpieces of sediment which are dislodged as a result of the action of thecutting tip will pass through the hollow body without causing anobstruction. Furthermore the configuration of the valve member is suchthat it is substantially cylindrical and as a result when it isintermediate of the retracted and extended position it is not possiblefor detritus or pieces of sediment that are dislodged by the action ofthe cutting tip to become jammed between the wall of the hollow body andthe valve member and which will prevent the complete retraction of thevalve member. In addition whilst the valve is open the clearing elementcan be moved to its extended position in order to ensure that anydeposits which may collect on the valve seat 117 can be removed and toclear any blockages which may develop within the inlet 111.

If desired the valve may be associated with a control means which willperiodically activate the delivery of fluid to the fourth and thirdspaces 147 and 146 respectively to cause the clearing element to becyclically moved from the retracted position to the extended positionand then to the retracted position to maintain the region above thevalve member and drain clear of sediment. This cyclic action may beeffected manually or automatically.

The second embodiment also provides a means whereby it is possible tovisually determine the state of the valve by observing the degree ofextension of the valve member 116 from the body and the degree ofextension of the rod 128 from the valve member 116. In addition asuitable locking means in the form of a locking ring 152 is provided onthe first end cap 123 to lock the valve member 116 in an open or closedposition as desired. The locking ring 152 is supported from the firstend cap and is adapted to be rotatable on the second end cap and aroundthe body of the valve member 116 whereby as a result of such rotation inone direction or the other the locking can lock the valve member inposition or enable it to be moved.

According to another embodiment of the invention which is a variationwhich can be used with either of the first and second embodimentsdescribed above, the clearing element may be mounted such that on itsaxial movement from the retracted position to the extended position, itis caused to undergo rotation to facilitate its penetration through anydeposit in the region of the drain outlet.

It should be appreciated that the scope of the present invention neednot be limited to the particular scope of the embodiments describedabove. In particular, the movement of the valve member and the clearingelement may be effected by any suitable means and need not be limited tothe hydraulic drive described in relation to the embodiment.Furthermore, the valve according to the invention need not be limited toutilisation with drain outlets but may also have application to valveslocated in flow lines or in any suitable application for valves.

The claims defining the invention are as follows:
 1. A valve comprisinga body adapted to be associated with an opening in the wall of a fluidreservoir or flowline, to provide a flow path, from an inlet at saidopening, to an outlet, a valve seat located across the flow path at theinlet, a valve member movably supported from the body to be movablebetween a closed position at which it is in sealing engagement with thevalve seat and an open position at which it is spaced from the valveseat, an elongate clearing element for clearing scale or sediment in theregion of the opening, the clearing element being slidably supportedwithin the valve member for axial movement within the valve member, theclearing element having an outer end which is movable towards and awayfrom the valve member between an extended position at which it extendsfrom the valve member through the valve seat beyond the opening and aretracted position closely adjacent the valve member, the valve memberfurther including a first drive means, which includes at least one of aseal and a piston, being received in a cylindrical first chamber whichis concentric to the valve member, the first drive means defining twospaces within the chamber and the spaces being capable of receivingpressurized fluid for acting on the drive means to effect said movementof the valve member, the elongate clearing element including a seconddrive means that includes at least one of a piston and a seal, andwherein the valve includes at least a third space for receivingpressurized fluid for acting on the second drive means for effectingsaid axial movement of the clearing element.
 2. A valve as claimed atclaim 1 wherein the valve member is provided with a first seal at oneend which is proximate the valve seat wherein the first seal is inengagement with the valve seat when the valve member is at its closedposition to sealingly close the valve, and wherein the first drive meansincludes a second seal located at the other end of the valve member. 3.A valve as claimed at claim 1 wherein the second drive means is receivedin the chamber and separates the second and third spaces.
 4. A valve asclaimed at claim 1 wherein the first drive means includes a seal locatedintermediate the length of the valve member.
 5. A valve as claimed atclaim 1 wherein one end of the valve member extends beyond the chamber.6. A valve as claimed at claim 1 wherein the valve member is hollow anda second chamber is defined within the valve member around a portion ofthe clearing element received therein and wherein the second drive meansinclude a seal provided with the portion of the clearing element andreceived in the second chamber to subdivide the second chamber into twospaces, one of the two spaces including the third space, and the otherof the two spaces being a fourth space capable of being pressurized toeffect said movement of the clearing element.